diff --git a/.github/requirements/build-requirements.in b/.github/requirements/build-requirements.in
index 9263954f3545..b5c702ee7643 100644
--- a/.github/requirements/build-requirements.in
+++ b/.github/requirements/build-requirements.in
@@ -1,7 +1,7 @@
 # Must be kept sync with build-system.requires at pyproject.toml
 setuptools!=74.0.0
 cffi>=2.0.0; platform_python_implementation != 'PyPy'
-cffi>=2.1; python_version >= '3.15' and platform_python_implementation != 'PyPy'
+cffi>=2.1.1; python_version >= '3.15' and platform_python_implementation != 'PyPy'
 maturin>=1.14.1,<2
 
 # Must be kept sync with build-system.requires at vectors/pyproject.toml
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index c2dfd026b986..a826020d9238 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -8,6 +8,8 @@ Changelog
 
 .. note:: This version is not yet released and is under active development.
 
+* Require CFFI 2.1.1 or newer on Python 3.15 to avoid an ABI issue in
+  earlier CFFI releases.
 * :func:`~cryptography.hazmat.primitives.serialization.load_der_private_key`
   and :func:`~cryptography.hazmat.primitives.serialization.load_pem_private_key`
   now accept :rfc:`5958` ``OneAsymmetricKey`` (PKCS8 version 2).
diff --git a/pyproject.toml b/pyproject.toml
index 4b6dbbac5331..710e37756753 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ requires = [
 
     # Must be kept in sync with `project.dependencies`
     "cffi>=2.0.0; platform_python_implementation != 'PyPy'",
-    "cffi>=2.1; python_version >= '3.15' and platform_python_implementation != 'PyPy'",
+    "cffi>=2.1.1; python_version >= '3.15' and platform_python_implementation != 'PyPy'",
     # Used by cffi (which import distutils, and in Python 3.12, distutils has
     # been removed from the stdlib, but installing setuptools puts it back) as
     # well as our build.rs for the rust/cffi bridge.
@@ -52,6 +52,7 @@ requires-python = ">=3.9,!=3.9.0,!=3.9.1"
 dependencies = [
     # Must be kept in sync with `build-system.requires`
     "cffi>=2.0.0; platform_python_implementation != 'PyPy'",
+    "cffi>=2.1.1; python_version >= '3.15' and platform_python_implementation != 'PyPy'",
     # Must be kept in sync with ./.github/requirements/build-requirements.{in,txt}
     "typing-extensions>=4.13.2; python_version < '3.11'",
 ]